Pile type fabrics are textile products characterized by an exposed face that has fibers or groups of fibers, i.e., yarns, standing upright in the direction perpendicular to the plane of the product. In so-called loop piles the fibers form upstanding loops with the ends of the loops attached to a support and the bend of the loop presented outwardly from the support. In other, so-called, cut piles, the bends of the loops are shaved so that free ends of the fibers point outward from the support. Pile type fabrics are generally more resilient and abrasive resistant than textile products of similar composition that are formed from fibers that largely lie parallel to the plane of the textile product.
One method of fabricating conventional pile type fabrics uses adhesives to glue the fibers to the support. A variety of this method is called flocking. It involves depositing chopped fibers oriented with their ends penetrating to a shallow depth into a bed of adhesive. In general, flocked fabrics are too delicate to deploy in high energy absorbing utilities such as flooring products and have other drawbacks such as reduced options for coloring or texturing.
Other pile fabrics are made by mechanically attaching the fibers, such as by tightly weaving or knotting the fibers into a support sheet. These fabrics are more robust than flocked fabrics and can be made into carpets. However, the processes for making such mechanically attached pile fabrics are generally slow and expensive. Some pile fabrics, such as stitched, needled, knitted, and tufted piles, use both mechanical attachment and copious quantities of adhesive applied to the support on its side opposite the pile for increased fabric stability. Despite technological advances for making these, fabrication complexity and adhesive systems provided to reduce fabric weight contribute to high cost of manufacture.
Pile fabrics formed by crimping yarns and attaching them to a support sheet are also available.
U.S. Pat. No. 3,708,384 discloses pile fabric formed by sonically inducing fusion bonding thermoplastic yarns to a thermoplastic backing on a bond line formed in the cross machine direction. The composite is advanced in the machine direction while the yarn supply is pushed toward the previously formed bond line to form a crimped pile and these steps are repeated.
U.S. Pat. No. 2,787,571 discloses a process in which intertwined fibers in warp yarns are intermittently adhesive bonded to a stretched backing layer. The warp yarns are attached only where the surface of the fibers contact the backing. When the backing is relaxed, the unbonded segments of the warp yarn fibers are forced into upstanding pile loops.
My U.S. Pat. No. 5,707,710 discloses a composite sheet suited for artificial leather which is made by impregnating a fabric having an interior yarn network and an outer layer of well separated fibers that loop in and out of the yarn network with an elastomeric resin. The method of making the composite sheet involves stitchbonding, knitting or weaving a fabric with elastic yarns and contracting the fabric to increase the number of tie points per centimeter.
My International Publication No. WO 94/19523 discloses an abrasion-resistant composite sheet of a resin-impregnated fabric formed from a lightweight nonwoven fibrous layer attached to a contracted planar network of yarns.
Conventional pile structured fabrics share the basic problem that dust and dirt tend to penetrate into the interstices between the fibers or yarns forming the pile. These contaminants collect at the roots of the pile and promote bacterial growth that creates a health hazard. To remove the dirt and sanitize the product the pile elements must be bent and parted so as to provide access to a cleaning tool. Additionally, spilled liquids can flow through the pile to the substrate and cause delamination. Solid sublayers that block liquid from passing to the substrate exacerbate wetness at the pile roots. This can increase the growth of bacteria and prevent moisture escape from wet subflooring such as drying concrete, and thereby contribute to separation of the floor covering product from the subfloor.
Traditional pile structured products also frequently suffer from excessive matting, that is, the collapsing of the pile under the load or repetitively applied weights, such as that which results from heavy foot traffic applied to carpets. Matting causes the pile to compact that makes dirt removal more difficult and gives the product a flat, undesirable prematurely worn appearance. The customary solutions to matting of piles have been to utilize high denier fibers that are stiff and more resilient but which detract from softness of the surface, and to shorten the height or the pile and/or to pack the pile elements closely together to give each other support. Short pile structures tend to lack a plush feel and closely packed pile elements add to the gross weight and cost of the product.
Laminate structures with relatively dense and flat face layers to resist dust penetration and pile collapse have recently been developed. These include using dense fibrous structures that are partially or fully filled with a resin, as disclosed in U.S. Pat. No. 4,035,215 (Goldstone), and U.S. Pat. No. 6,063,473 (Zafiroglu) and a film to cover the pile, as disclosed in U.S. Pat. No. 3,860,469 (Gregorian et al.). These laminate structures also lack a plush textile feel and decorative diversity of traditional pile materials.
Certain products made of flat textile fabrics laminated onto adhesive layer-coated reinforcing underlayers are described in WO 99/19557 and U.S. Pat. No. 5,965,232 (Vinod). These provide improved resistance to dust infiltration and bacterial growth but lack the plush hand of pile structured fabric and are susceptible to delamination and edge-fraying.
U.S. patent application Ser. No. 10/307,186, which is hereby incorporated by reference herein, is directed to a textured composite having a fibrous outer layer bonded at selected parts of its area with an adhesive layer such that the fibers of the outer layer are fully embedded in the adhesive within the bonded parts. Elevated areas between the bonded parts are substantially adhesive free and have loop pile like qualities.
It is desirable to obtain a textile product that has densely populated, deep (i.e., tall element) pile structure that is simple and inexpensive to fabricate, provides enhanced blocking of dirt infiltration and resistance to bacterial growth, resistance to matting without using very high pile density and stiff pile yarns, is easily sanitized, and which can use a broader selection of fibrous materials than heretofore available while providing plush, resilient, soft textile feel and good abrasion resistant properties of true pile structure.